Sliding systems with onboard small linear motor have been used in years in extensively increased fields including semiconductor industries, various assembly machines, and so on. Modern sliding systems with onboard linear motor are further finding a multitude of potential applications. Advanced sliding systems with onboard linear motor, nevertheless, are needed to meet anticipated design specifications of more miniaturization in industries as diverse as semiconductor fabricating machines, assembly machines, and so on, making it possible to work with high speed, high acceleration/deceleration, fast response, high position-control.
A prior sliding device with onboard linear motor is disclosed in, for example Japanese Patent Laid-Open No. 2002-010617 in which the onboard linear motor employs a moving-magnet principle. The prior sliding device is made smaller in construction. With the prior sliding device recited here, an auxiliary magnet is placed out of N-pole of forward and aft magnetic end poles of the field magnet to makes up for the magnetic flux pattern at the end pole of the field magnet, thereby making the magnetic sensor element easier to detect an accurate position of the field magnet. Moreover, the prior sliding device is particularly comprised of a bed secured to any one of relatively sliding members, a table mounted to the other and allowed to move lengthwise of the bed through a linear motion guide unit, a field magnet secured on one side of the table facing on the bed and composed of magnet strips juxtaposed in an array that their polarities alternate in an sliding direction of the table and are unlike at forward and aft ends of the field magnet, an armature assembly having armature windings lying on one side of the bed facing on the table in opposition to the field magnet for carrying a current to produce a magnetomotive force that gives propulsion to the field magnet to move the table towards the desired position, and a magnetic sensor secured to the bed in opposition to the field magnet to detect strength and direction of magnetic flux.
A prior X-Y table system is disclosed in, for example Japanese Patent Laid-Open No. H09-123034 in which an output table is controlled with high acceleration/deceleration to move towards the desired position in any of X-direction and Y-direction. With the prior X-Y table system recited earlier, X-axis table and Y-axis table are not overlaid up and down in vertical direction, but staggered each other in horizontal direction. On the X-axis table, there is provided the output table that is allowed to associate with both the X-axis table and Y-axis table to move in X-Y directions towards the desired position. The X-axis table and Y-axis table are respectively provided with the driving means of linear motor. Moreover, there are provided linear motion guide units to guide the tables for linear movement while keeping constantly the moving parts of the linear motors spaced away from the stationary counterparts. The output table is associated with the Y-axis table through another linear motion guide unit that is connected with the Y-axis table at the guide rail thereof and connected with the output table at the slider thereof. With the prior X-Y table system constructed a s stated earlier, thus, the X-axis table and the Y-axis table are respectively actuated with their associated driving means of linear motor while the output table is related in motion with the X-axis table through an X-axis coupling of linear guide and also with the Y-axis table through a Y-axis coupling of linear guide.
Also disclosed in, for example Japanese Patent Laid-Open No. 2000-193060 is a pick-and-place system having a slider unit composed of a slider and a sliding guide. With the prior slider unit recited here, a return spring is constructed to make no engagement with other component such as a guide rod even after squeezed. The return spring for the slider unit is split into short parts that are joined each other through spring shoes, which fit into either the slider or the guide rod. The slider unit constructed as stated earlier is employed for the X-axis sliding mechanism of the pick-and-place system to allow a top block to make pick-and-place operation or performance by virtue of a cam arrangement.
However, any of the prior X-Y table systems recited earlier couldn't shun becoming bulky in construction. Moreover, the pick-and-place system constructed as stated earlier would need much space for, especially, the semiconductor fabricating machine where many slider units are used in juxtaposition. Thus, it would be inevitable that the semiconductor fabricating machines such as semiconductor mounting equipments and so on as a whole is bulky and space-hungry.